Releasing clamp



I Dec. 24, 1935. K HAWLEY 2,025,346

RELEASING CLAMP Original Filed July ll, 1929 Z l /o f w am/w l l if I A52 l A? /Z /6 w 6 V p /0: 0 1

Patented Dec. 24, 1935 UNITED STATES PATENT OFFICE RELEASING CLAMPOriginal application July 11, 1929, Serial No. 377,565, now Patent No.1,916,950. Divided and this application August 30, 1932, Serial No.

8 Claims.

This application is a division of my co-pending application for patentfor Releasing clamps, now Patent No. 1,916,950 filed July 11th, 1929 andgiven Serial No. 377,565.

The invention relates to means for suspendingthe conductors of currenttransmission lines and has special reference to suspension clamps.

It is well known that it is customary to support transmission lineconductors by means of clamps located at the bottom of strings or chainsof insulators which are in turn hung from towers located considerabledistances apart. It is a fact that snow or ice and sleet frequentlycollects on the conductor at one side of a point of suspension but noton the other side as for example at the edge of a storm area or whenthere are differences in temperature or other climatic conditions alongthe line. Furthermore it frequently occurs, especially in mountainoussections that one or more spans of the conductor may be subjected to theinfluence of high winds. In either event, and under other circumstancesof a more or less analogous nature which may readily suggest themselves,it is apparent that there is an excessive strain at one side of asupporting tower and unless the tower is of excessively heavyconstruction, that is to say heavier than would reasonably be provided,there is a certain danger that the tower may be pulled out of plumb. Ofcourse under such circumstances the insulator strings are also pulledout of place and damage thereto may easily occur.

It is with the above facts in view that I have devised the presentinvention which has for its general object the provision of a conductorclamp capable of automatically releasing or at least decreasing its gripupon the conductor upon the occurrence of an excessive strain at oneside or the other of the clamp and whatever support it is hung from.

An important object of the invention is to provide a releasing clampwhich will under ordinary conditions exert a powerful clamping actionupon the cable but which is so constructed as to permit the cable toslip through until the strains have become equalized.

Another object is to provide a releasing clamp of this type which mayregain its clamping ability or re-exert its clamping action upon thecessation of the abnormal strain previously operating to bring about thereleasing action.

Another important object is to provide a clamp embodying cam means foreffecting the release.

Yet another object of the invention is to provide a clamp having anelement adapted to be temporarily distorted so as to release the gripupon the conductor so that the latter may slip through and adjustitself, it being also a feature that the distorted element may reassumeits natural or normal condition so that the device may regain itsclamping function without it being necessary to make any repairs orreplacements.

Another important object of the invention is to provide a clamp of thistype which does not depend on springs for its holding action but whichhas, on the contrary, positive means for applying a clamping force tothe conductor.

An additional object is to provide a device of this type which willconsist of but a few parts, 15 certain of which are more or lessstandard among insulator manufacturing companies, and which willconsequently be inexpensive to make in ad- .dition to being easy toapply or install, positive in action, efficient and durable in service,and a general improvement in the art.

To the attainment of the foregoing and other objects and advantages, theinvention preferably consists in the details of construction and thearrangement and combination of parts to be hereinafter more fullydescribed and claimed, and illustrated in the accompanying drawing inwhich:

Figure 1 is a side elevation of a. clamp constructed in accordance withmy invention and showing it in normal position upon a conductor,

Figure 2 is a longitudinal section with the released position indicated,

Figure 3 is a central cross sectional view,

Figure 4 is a detail view of the upper clamping member.

Referring more particularly to the drawing it will be observed that Ihave shown a clamp for supporting a conductor I, the clamp embodying amain or lower clamping member 2 having a transversely curved seat 3 forthe conductor, this seat being, moreover, curved longitudinally so thatthe ends thereof will flare away from the conductor to avoidbringing-any bending strains thereon such as might occur in the event ofvibration or dancing of the conductor. This lower clamping member 2 isrepresented as provided at one side with bosses 4 having verticallyextending holes 5 therethrough for the reception of clamping bolts to bedescribed. At its center the member 2 is shown as provided withoppositely extending lateral trunnions 6 which are preferably integraland which are represented as having downwardly elongated heads I.

Cooperating with the lower member or body 2 b5 to be explained.

The holding means is here represented as comprising J-bolts II whichhave their. shanks extending through the holes 5 in the bosses 4 andwhich have their hooked ends overlying the reduced extensions Ill.Beneath the bosses these J-bolts are provided with nuts l2, it beingpreferable that spring washers |3 be interposed between the nuts and theundersides of the bosses to prevent accidental unscrewing of the formerand. also to provide a very limited yieldability.

The suspension means is here represented as comprising a pair of links I4 straddling the member 2 and formed with elongated openings l5 for thepassage of the'trunnions 6, the downwardly prolonged heads I of thesetrunnions projecting beyond the lower ends of the openings l5 so as toprevent lateral displacement of the links with respect to the clamp whenin service. At their upper ends the links may be apertured as at 16 forconnection with a suspension element, not shown, at the lowerend of astring or chain of connected insulators. The axis of the trunnions B ispreferably at substantially the longitudinal center of the conductor,which is the logical and most advantageous location of the pivot. Abovethe openings t5 the links are provided at their inner faces'with' flatledges H which cooperate with pairs of lugs l8 projecting laterally fromthe opposite edges of the clamping member 8.

The device is applied to the conductor by placing the clamping members2' and 8 below and .above the conductor, respectively, and applying theJ-bolts ll. Suspension is effected by engaging the links M upon thetrunnionst and then connecting the links with the string of insulatorsfrom which the conductor is to be suspended. When the nuts [2 aretightened the upper member 8 will be drawn down into clamping relationto the member 2 and conductor i so that there will beanadequate gripupon the latter. Under normal circumstances the ledges or shoulders I!are spaced slightly below the lugs 68 as clearly indicated in Figures 1and 3- so that there will be no wear on these parts during limitedswaying or swinging movement of the clamp with respect to the suspensionlinks.

In the operation, it is apparent that upon breakage or overloading ofthe conductor at one side or the other of the clamp the insulatorstring, not shown, and the clamp carried thereby will swing lengthwiseof the conductor, whereupon the ledges I! will engage against one or theother pair of lugs l8 and apply upward pressure upon the upper clampingmember, the pressure obviously being greater at one end than at theother. The upper clamping member then fulcrums upon or within one of theJ-bolts II and presses upwardly against the other with such force as tospring it, flex or distort' it out of its normal condition, therebyrelieving the pressure exerted upon the conductor by the upper clampingmember and permitting the conductor to slip through until a state ofequilibrium or balance of strain has been established, subsequently towhich the natural resilience of the flexed or distorted J-bolt willcause it to resume its natural condition re-exerting the clamping actionon the conductor- From the foregoing description and a study of thedrawing it will be apparent that I have thus provided a very simplyconstructed and easily installed clamp which will have the necessaryholding action under normal conditions and which will be capable ofautomatically releasing in the event of an unusual strain coming uponthe conductor at one side or the other of the clamp. It is believed thatthe construction, operation and advantages will be readily apparent toone skilled in the art without further explanation.

While I have shown and described the preferred embodiment of theinvention, it should be under stood that the disclosure is merely anexemplification of the principles involved as the right is reserved tomake all such changes in the details of construction as will widen thefield of utility and increase the adaptability of the device providedsuch changes constitute no departure from the spirit of the invention orthe scope of the claims hereunto appended.

Having thus described the invention, I claim:

l. A clampcomprising' a pair of clamping members, a pair of bolt meansfor securing the samein clamping relation upon a conductor, suspensionmeans, and cooperating means on the suspension means and one clampingmember for distorting and rendering one of said bolt means inefiective.

2. A clamp comprising the combination of a pair of clamping membersdisposable upon a con-- ductor, bolt means securing said members inclamping relation, suspension means connected with one of said clampingmembers, and cooperating means on the suspension means and the other ofsaid clamping members for flexing one of said bolt means and therebydecreasing the clamping action thereof.

3.- A clamp comprising a pair of clamping members, bolt means securingsaid clamping members in clamping relation upon a conductor, suspensionmeans, and cooperating means on the suspension means and the otherclamping member for flexing one of the bolt means whereby said otherclamping member may fulcrum upon the other bolt means. I

'4. A clamp of the character described comprising a lower clampingmember, an upper clamping member, bolt members for securingsaid clampingmembe-rs upon a conductor in clamping relation thereto, suspensionmeans, and cam means operable upon movement of the suspension means withrespect tothe lower clamping member for temporarily distorting one ofthe bolt members and decreasing the clamping action.-

- 5. A clamp of the character described comprising upper and lowerclamping members, bolt members securing said clamping members" inclamping engagement upon a eonducton suspension means, and cam means onthe suspension means engageable with the upper clamping member uponpivotal movement of the suspension means with respect to the clampingmembers for flexing one bolt member and rocking the upper clampingmember upon the other bolt member for decreasing the clamping action.

6. A clamp of the character described comprising a lower clamping memberhaving bosses thereon, an. upper clamping member having lateralprojections at opposite sides or its transverse center, bolts passingthrough the bosses and each embracing the upper clamping member formaintaining both clamping members in clamped engagement upon aconductor, suspension links pivotally connected with the lower clampingmember, and cam elements on the suspension links engageable with certainof said lateral projections upon pivotal movement of the links withrespect to the clamp for forcing one end portion of the upper clampingmember upwardly and distorting one of said bolts upwardly.

7. A conductor supporting clamp comprising an assembly of clampingmembers disposable upon a conductor, securing means for holding theassembly together, suspension means pivotally connected with theassembly, and means on the suspension means coacting with one of theclamping members for temporarily distorting one of the securing meansfor relieving the pressure exerted by the assembly upon the conductor.

8. A conductor supporting clamp comprising a lower clamping member andan upper clamping member adapted to receive a conductor between them,J-bolts connected with the lower clamping member and overlying the upperclamping mem ber, suspension means pivotally connected with the lowerclamping member, and cam means operable upon swinging movement of theclamping members with respect to the suspension means for forcing oneend of the upper clamping member upwardly for temporarily distorting oneof the J-bolts and relieving the clamping action.

KENT A. HAWLEY.

